Mining machine



July 18, 1939. L E. MITCHELL 2,166,689-l MINING MACHINE Original Filed May 2 19324 5 Sheets-Sheet 1 nventor Cttorneg L. E. MITCHELL MINING MACHINE Julygls, 1939.

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l l MINING MACHINE o'riginai Filed May 2, 1952 5 sheets-sheet 4 I Snnentor: n' [Li-IM* 2me/@6e MINING MACHINE Original Filed May 2, 1952 5 Sheets-Sheet 5 v I'ltg. I5' 45 55 73 :inventor Mil/w, H7 MMVWM,

Patented July 18, 1,939

UNITED STATES PATENT OFFICE MINING MACHINE.

poration of Ohio Original application May 2, 1932,

Serial No.

608,585. Divided and this application December 30, 1937, Serial No. 182,488. Renewed May 11 Claims.

My invention relates to mining machines particularly of the type adapted to travel on a mine track and remain thereon to be braced thereby during operation.

One of the objects of my invention is to provide in kerf-cutter feeding mechanism, brake mechanism in combination with self-locking worm gearing to counteract the tendency of vibrations of the kerf-cutter during feeding operations to cause the worm gearing to creep.

A further object of my invention is the provision of improved and eii'icient turnover head mechanism for the kerf-cutter of a mining machine, comprising self-locking worm gearing combined with brake mechanism to hold the keri- `cutter in adjusted position by oounteracting the tendency of vibrations of the kerf-cutter to change the adjusted position thereof during rectilinear feeding operations. Y

Another object of the invention is the provision of improved and eiicient swinging feeding mechanism for a kerf-cutter, comprising self-locking worm gearing combined with brake mechanism to hold the kerf-cutter in adjusted positions by counteracting the tendency of vibrations of the kerf-cutter to change the adjusted position thereof during swinging feeding operations thereof.

More particularly it is the object of the present invention to combine brake mechanism with pawl and ratchet feeding mechanism connected to a kerf-cutter, to prevent retraction of feed of the kerf-cutter during reverse impulses of the feeding pawl.

A further object of the invention is the pro- Vision of improved and efcient feeding mechanism for a kerf-cutter so compactly arranged in association with turn-over head mechanism for the kerf-cutter, as to maintain a minimum overall height of the machine both when operating to cut horizontal kerfs and when operating to produce upright kerfs.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the accompanying drawings,

Fig. 1 is an elevational View of my improved mining machine illustrated as performing a bottom cutting operation;

Fig. la illustrates a top cutting operation;

Fig. 2 is a plan view of the complete mining machine shown in Fig. 1, showing the mechanism for swinging the cutter bar;

Fig. 3 is a bottom plan View of the structure shown in Figs. 1 and 2, showing the power-operated mechanism for varying the elevation of the cutter bar relative to the truck on which a turntable is mounted;

Fig. 4 is a detailed view of an individual screwpost elevatingfmechanism for the turntable including an individual controlling clutch to secure variation of inclination of the cutter bar on either a longitudinal axis of the turntable or a horizontal transverse axis thereof;

Fig. 5 is a longitudinal enlarged sectional elevation of that portion of the mining machine shown in Fig. l which embodies a turret for swinging the cutter bar on a lowered horizontal longitudinal axis combined with an additional turret for swinging the cutter bar in'` its own plane;

Fig. 6 is an enlarged plan view of the righthand portion of the structure shown in Fig. 5;

Fig.v 7 is a sectional elevation of the controlling mechanism shown in plan at the upper left-hand portion of Fig. 6, taken on the line 'l-l of Fig. 9, looking in the direction of the arrows;

Fig. 8 is a sectional plan view taken on the line 8 8 of Fig. '7;

Figs. 9 and 10 are more or less diagrammatic views to illustrate the power transmission and controlling mechanism for swinging the turrets on their respective axes;

Fig. 11 is an enlarged sectional elevation taken as indicated by the line II-Il of Fig. 7, looking in the direction of the arrows;

Fig. 12 is an enlarged sectional elevation taken as indicated by the line I2|2 of Fig. 9, looking in the direction of the arrows; v

Fig. 13 is an enlarged sectional elevation to show the clutch controlling mechanism for the power transmission from the motor on the turntable to the turret rotatable on the horizontal axis shown in Fig. 5;

Fig. 14 is an elevational View of the manual mechanism for operating the disc clutch shown in Fig. 13;

Fig. 15 is a sectional elevation taken on the line l5-l5 of Fig. 14, looking in the direction of the arrows;

Fig. 16 is a sectional elevation taken on the line |6-I6 of Fig. 14, looking in the direction the arrows; and

Fig. 17 is an illustration of my machine in operation during transportation, in which the cutter bar is held in a vertical position.

This application is a division of my application Serial No. 608,585, led May 2, 1932.

By referring to Figs. 1 and 2, there is seen a kerf-cutting mining machine comprising my invention, including at the outer end portion a cutter bar 21 and having a truck frame 28 mounted on wheels 29, 29 which are adapted to travel on a mine track 30 and be laterally braced thereby during feeding movements of the cutter bar. This kerf-cutting machine is of the general type shown in the Levin Patent No. 1,353,054, granted September 14, 1920 for an improvement in Mining machines, which includes the turntable, a cutter bar connected thereto for rotation therewith on an upright axis, mechanism for swinging the turntable and the cutter bar on such upright axis relatively to the truck and power operated mechanism for varying the elevation and inclination of the turntable and the cutter bar relative to the truck.

The kerf-cutting mining machine shown in Figs. 1 and 2 also includes apparatus operated by an electric motor 3| on the truck frame 28 for propelling a mining machine along the mine track 38 at a transport speed or at a slow feeding speed. A motor 32 is mounted on the turntable 33 to rotate bodily therewith and is connected to rope gearing comprising a rope 34 for swinging the turntable together with the cutter bar relative to the truck on the upright axis of the turntable.

The truck-propelling mechanism for transportation and for traction feed, shown in bottom plan View in Fig. 3, comprises the sprocket chains 29' and 3| with the latter connected through speed reduction gearing 3| to the motor 3|. The construction for obtaining the fast speed for transportation and the slow speed for feeding purposes may be as shown in the Levin Patent 1,353,054 granted September 14, 1920.

The motor 3| on the truck frame 28 is also connected to the cable reel 35 which pays out or winds up the electric cable 33 for conducting electric power from a distant source of supply to the motor 3| on the truck and the motor 32 on the turntable.

The mechanism for elevating the turntable together with the cutter bar mounted thereon, is shown in Fig. 3, and comprises the sprocket chain 38 for rotating the Vertical screw-posts 39, 39, 39. Power may be transmitted to these screw-posts individually by the mechanism shown in Fig. 4 so as to effect variation of inclination of the turntable and the cutter bar on either a longitudinal axis of the turntable or a horizontal transverse axis thereof. As illustrated in Figs. 2 and 5 the armature, shaft 4E) of the motor 32 on the turntable extends horizontally forward and radially of the turntable.

At the forward end of the armature shaft 48 is a bevel pinion 4| which meshes with a horizontal bevel gear 42 secured to the vertical shaft 43 which is journaled in the bearing 44 of the auxiliary frame 45 rigidly secured to the turntable 33. Secured to the upper end of the vertical shaft 43 is a bevel gear 46 which meshes with a bevel gear 41 mounted on the left-hand end of the horizontal shaft 48 journaled in the frame 45. The bevel gears 46, 41 may be lubricated by oil from the closed chamber 48' through the nozzle 49. The journal bearings for the horizontal shaft 48 may be lubricated by oil from the closed chambers 50, through the oil holes 52, 53. A cover plate 54 closes the chambers 48', 58 and 5|, and the lubricant in these chambers may be replenished by virtue of the ports 52', 53', 54'.

At the right-hand end of the horizontal Shaft 48 as viewed in Fig. 5, is secured a gear 55 which meshes with a gear 56 onv the left-hand end of shaft 51 which is offset below the horizontal shaft 48 but is in the same vertical plane therewith at all times. The axis of the shaft 51 is also offset from and below the horizontal axis of the armature shaft 40.

As will be hereinafter explained, the shaft 51 is journaled in a horizontally extending arm or cylindrical bearing 51 of auxiliary frame 45. Turret frame or neck 58 is rotatably supported on the said extending arm 51 of auxiliary frame 45 along the horizontal axis of the shaft 51. At the right-hand end of the shaft 51 is a bevel gear 59 which meshes with a horizontal bevel gear 60 as said gear is viewed in Fig. 5. The gear 60 is journaled loosely on the shaft 6| and the latter is journaled in the bearing 62 of the cap 63 rigidly secured to the turret 58. The shaft 6| is also journaled at its lower portion to the bearing 64 which is secured rigidly to the second-named turret frame 65. Rigidly connected to the lower end of the turret 65 is a cutter bar 21 in position to occupy a plane at right angles to the shaft 6|. Guided along the periphery of the elongated cutter bar 21 is an endless cutter chain 66 which meshes with a driving sprocket 61 secured to the lower end of the shaft 6|. By means of the clutch 68, the bevel gear 60 may be connected with the shaft 6| to drive the sprocket 61 and the chain cutter 66. 'Ihe clutch 68 may be manually operated from either side of the neck turret 68 by means of the levers 69, 69 shown in Figs. l and 6. By moving one of the levers 69 the rock shaft 18 will actuate the shipper 1| to throw the clutch 68 in or out as shown in Fig. 5, it being locked in each position.

In order to rotate the neck turret 68 and its connecting neck 58 on the horizontal axis of the shaft 51, power transmission mechanism is arranged between the spur gear 55 and the worm gear 12 which is rigidly connected to the neck 58. By referring to Fig. 15 which is a sectional view taken on the line |5| 5 of Fig. 14, looking in the direction of`the arrows, it will be seen that the gear 56 meshes with an idler 12 and that the latter meshes with a gear 13 which in turn may be connected to the shaft 14 by means of a friction clutch 15, as shown in Fig. 13. The friction clutch 15 may be thrown in or out by means of a lever 16 shown in Fig. 14. The lever 16 is pivoted at 11 and is provided with an adjustable screw 18v held in fixed position by the nut 19 so as to engage the upper end of the actuating arm 80 which is urged against the screw 18 by the spring 8|. The lower end of the actuating arm 80 is keyed to the rock shaft 82 (Figs. 14, 16) which extends into the housing 83 rigidly connected to the depending supporting bracket 45 (Fig. 15) on the auxiliary frame 45. Within the housing 83 is a shipper 84 connected to the clutch operating element 85 which is shown in Fig. 13 in position to move the outer set of discs of the friction clutch toward the annular flange 86 of the clutch element 81. The inner set of friction discs is connected to rotate with the clutch element 81 which is keyed to the shaft 14. The outer set of friction discs is connected to the clutch element 88 which is secured to the gear 13 to rotate therewith. Therefore, when the motor 32 on the turntable 33 is operating in one direction or. the other, power will be transmitted through the train of gearing shown in Figs. 5 and 16 through the clutch element 88, and when the lever 16 is actuated to apply the friction clutch 15 the shaft 14 will be rotated accordingly.

Mounted on the shaft 14 is a worm 89 which meshes with a wormawheel 9U-, the latter being keyed on the shaft 9| as shown in Figs. 5 and 9.- The shaft 9| carries a worm 92 which meshes with a large worm gear 12 secured on the neck 58. (Fig. 16). Therefore, when the friction clutch 15 is applied to transmit power to the shaft 9| fromthe motor 32 on the turntable, the turret frame 58 will be rotated on the axis of the shaft 51 while held in place by the split retaining ring 93, thereby revolving the cutter head 65 about the axis of said shaft 51. In this way the rotation of the turret frame 58 and the neck turret 68 will be on the offset support 45 about the axis of the shaft 51 which is offset below the axis of the shaft 48. Consequently, since the shaft 51 is in a vertical plane that extends through the shaft 48 and occupies a position below the axial line of the latter, the kerf-cutter may readily occupy a horizontal position at the floor level, as indicated in Fig. 1. Furthermore, by reason of the offset position of the shaft 51 and the axis of the neck 58, the neck turret 68 and the attached cutter bar 21 may be rotated on a relatively low horizontal axis so that when the cutter bar is in a top horizontal cutting position it will lextend only a short distance above the upper side of the turntable 33.

Also, by reason of the offset position of the axis of the neck 58, the neck turret 68 and the cutte-r bar may be rotated until the cutter bar assumes a shearing or vertical position, as illustrated in Fig. 17, whereby the machine may be transported from place to place on the tracks 30 or may be employed to make a vertical cut and yet maintain the entire cutter bar 21 and the neck turret 68' below a horizontal plane passing substantially through the top of the turntable 33. Still further, by reason of the offset position of the axis of the turret 58, when the cutter bar 21 is in a position for making a lower horizontal out as illustrated in Fig. 1, the turret frame 68 is entirely below the above mentioned horizontal plane passing through the top of the turntable 33.

It is thus seen that my device may be employed in a low ceiling mine of a height only slightly greater than the height of the machine as determined by the turntable, and provides 'both a vertical and lower horizontal cutting device. Still further, if the mine roof or ceiling is low but still slightly above the top horizontal plane of the turntable 33, my device may also be employed for making a top horizontal cut in addition to the above-mentioned cuts.

After the chain kerf-cutter has been adjusted on the axis of the shaft 51, either to any one of its horizontal positions or to a vertical or shearing position or to any intermediate inclined position, the friction clutch 15 may be released by releasing the lever 16, whereupon the sets of friction discs will separate sufficiently to permit the self-locking worm` gearing 89, 90 and 92, 12 to effectively hold th-e kerf-cutter in the adjusted position.

In order to swing the kerf-cutter on the axis of the shaft 6| in either direction at a feeding speed, power transmission mechanism is connected between the bevel gear 60 and the large worm wheel 94 which is secured to the cutter bar head turret 65 as illustrated in Fig. 5. Secured the cap screws ||-vto the eccentric cam 95 and is.

of sucient diameter to overlap a portion of th circular strap 96, shown in Fig. 5,.

The pawl and ratchet mechanism is shown in detail in Figs. '1 and 11 and is diagrammatically illustrated in Fig. 9. This pawl and ratchet mechanism is mounted in a housing |02 which is provided at its upper side with a closure |03. Reversely arranged ratchet wheels |04 and |05 are keyed to the shaft |06 and are confined between a shoulder on the upper end portion of the shaft |06 and a circular plate |01 which is secured by means of the cap screw |08 to the upper end of the shaft |09 of reduced diameter. Mounted on the inverted cup-shaped support ||0 are the reversely arranged pawls I I2 which are pivoted to the support i I0 on the pin I3. A spring I4 between the arms I5 and I I6 extending from the pawls III and I|2, urges the latter toward their respective ratchet wheels |04 and |05.

Between the cup-shaped support |I0 and the ratchet wheels |04, is located a cylindrical pawl releasing and adjusting device |I1 which is provided with openings I8, I8 as shown in Figs. 9 and 11. The upper central portion of the cupshaped pawl releasing and adjusting device ||1 is connected to the shaft I I9 which is journaled in the sleeve |20 at the upper central portion of the cup-shaped support I0. To the upper end of the shaft I9 is secured an arm |2| the outer end of which is provided with a support |22 for the spring-pressed pin |23, the upper end of which is provided with a knob |24, the lower end of which pin may extend into one of the depressions |25 (Fig. 6) in the plate |26 secured to the upper side of the cap or cover |03. When the lever |2| is in central position each of the pawls III and I|2 is held out of engagement with its respective ratchet wheel |04 and |05 and no movement of' the cutter bar 21 will take place about the axis of the turret 65. When the lever |2| is moved in one direction from its central position, one of the pawls or I|2 will be maintained out of engagement with its ratchet wheel and the other pawl will be permitted to engage its ratchet wheel, and the position of the lever |2| will regulate the extent of movement of the engaged ratchet wheel by determining the number of teeth of said ratchet wheel engaged during each stroke of the pawl upon each rotation of the eccentric cam 95. That is tosay, the rate of feed of the cutter bar in either direction of swinging movement may be adjustably regulated. Whether the shaft |06 is rotated in one direction or the other, the actuating ratchet Wheel will be held against reversal when its pawl reverses, by the adjustable brake mechanism shown in Figs. 7 and 8, comprising the brake-band |21 which is associated with the brake wheel I 28 secured to the lower end of the shaft |06. This brake mechanism also prevents creeping between worm gear elements 94, |39 as best seen in Fig. 9. As shown in Fig. 7, the shaft |06 is journaled in a bearing |29 of a block |30 secured at |3| to the housing |02. Inasmuch as the pawls are reciprocated upon rotation of the cam 95, the frame I I0 has its sleeve |20 on its upper side mounted in the bearing |32 while the lower portion of the support ||0 is secured to the annular member |33 journaled on bearings on the block |30.

As shown in Fig. 12, the bevel gear |35 is connected to the circular plate |40 by means of a shear pin |4| and the plate |40 is keyed to the shaft |36. By means of the cap screw |42, the plate |40 is retained in place on the shaft |36,y and the same cap screw may be used to retainv in place the keeper |43 for the shear pin |4|. Since the worm |39 meshes with the large worm gear 94, swinging feeding movement of the kerf cutting mechanism is effected by operation of the worm gearing |39 and 94. (Fig. 9). If the cutter bar should engage unusually hard material such as a sulphur ball, or if the feed should be inconsistent with the hardness of the material, the pin |ll| will be sheared to protect the transmission mechanism. Such shearing of the pin 4|, however, will not interfere with the selflocking feature of the worm gearing |39, 94 to hold the cutter bar 21 in interlocked relation with the first turret frame 68'.

The track-mounted mining machine may be operated in various ways to produce kerfs by traction feed, either in horizontal planes or in vertical planes or in intermediate inclined planes, all at right angles to the working face. Traction feed for this purpose may be effected by controlling the truck-propelling mechanism to move along the mine track at feeding speed. The cutter bar may be adjusted in elevation and in inclination by the mechanism associated with the three screw-posts 39 between the truck fra-ine and the support for the turntable. The cutter bar may be swung arcuately either on the turntable axis or on the axis of the cutter head turret 65. When the plane of the cutter bar is parallel to the mine track sumping and withdrawal cuts may be made either in upright planes or in horizontal planes or in intermediate inclined planes.

In making a shear or vertical kerf at side openings, or near the ribs where the width of face is to be increased, it often becomes necessary to produce kerfs at angles varying from a plane extending at right angles to the face, as illustrated in the patent to Levin, granted November 19, 1935, for an improvement in mining machines. This may be accomplished with the mining machine disclosed in the accompanying drawings, by a combination of shearing action and traction feed, resulting in a wedge-shaped or V-shaped kerf of considerable opening at the working face and decreasing as it proceeds into the body of coal at the working face. The wedgeshape of the kerf so produced enables the cutter bar to be fed in and withdrawn after the cutting operation has been performed. The main turntable may be free to iioat at certain intervals both during such forward feeding movement and during withdrawal of the cutter bar, to avoid binding or cramping and so that the bar may be free to adapt itself to the cutting of such V- shaped kerf of no greater width than necessary, thereby reducing kerf-cutting to a minimum at the places where the widthof the face is tobe increased as aforesaid.

In order to retain the cutter bar locked in a stationary position at an adjusted angle, the mechanism shown in Fig. 16 is preferred. During mining operations vibrations of the cutter bar may tend to cause creeping between the worm gear elements 92, 12 and to prevent this I have mounted a spring pressed brake as shown at in Fig. 16, to act against an annular flange |1| on a nut |12 which is screw-threaded to the extension |13 and pinned thereto at the left-hand end of the worm shaft 9|. The brake |19 is maintained against rotation with respect to the casing |16. The' shaft 9| is mounted in the bearings |14, |15 in the casing |16 which is secured rigidly to the dropped support |11, as shown in Fig. 5. The casing |16 including the support |11 are rigidly connected to the depending bracket 45 and the latter in turn is rigidly connected to the auxiliary frame 45 xed to the turntable 33 and comprising a part thereof. The mechanism for swinging the turntable on the vertical axis relative to the truck is also provided with self-locking worm gearing to hold the turntable locked to the truck when it is clesired to hold the cutter bar stationary relative to the truck.

In order to lock the turntable 33 to the ring |83 (Fig. l) it is mounted on the adjusting screwposts 39. Locking devices |84 (Fig. 2) are associated with notches |85 in the periphery of the turntable 33. The ring |83 is carried by the pedestals |85 which depend therefrom and a nut |115 is threaded on each screw-post 39 as shown in Fig. 4. By means of the lever |81 the clutch |88 may be operated to control individual elevation of each nut |88 on the associated pedestal |85', the sprocket |89 being connected to the vertical screw-post 39 to rotate therewith.

By referring to Figs. 1 and 17, it will be seen that the overall height of the mining machine is relatively low, and the machine is therefore adapted to operate in a low roof mine chamber. However, the same machine may be operated in high roof mine chambers for shearing because of the high reach aiorded by the cutter bar 21 which is adjustable about the horizontal axis of the turret 65. The neck 58 is mounted on the truck for horizontal swinging movement on the vertical axis of the turntable 33. The axis of the turret 65 on which the cutter bar 31 is swingable extends at right angles to the horizontal axis of the turret 68. When the axis of the turret 65 is horizontal the cutter bar 21 may be moved in, a vertical plane to include shearing positions extending upwardly or downwardly relative to the horizontal and held in an adjusted position.

The vertical adjustableness of the turntable 33 as provided by the screw-posts 39, provides a machine which is particularly adapted for use in a low ceiling or low roof mine but which may also be employed to make a horizontal top cut in a relatively high ceiling or high roof mine. That is, with the turntable 33 raised to its maximum height as provided by the screw-posts 39 and with the cutter bar 21 positioned above the neck turret 68 a relatively high top cut may be made, in a high roof mine room or entry.

The provision of the neck 58 about an axis appreciably below the top of the turntable device, not only provides for the maintaining of the neck turret 68' and the cutter bar 21 entirely below the top of the turntable when the cutter bar is in the positions illustrated in Figs. 1 and 17, but also provides a relatively low positioning of the cutter bar 21 when it is in a top horizontal cutting position. While the cutter bar 21 extends slightly above the top of the turntable 33 when in said top horizontal cutting position, it extends thereabove only a small distance and unless the mine roof or ceiling is exceedingly low a top cut is possible.

It is also obvious that in the kerf-cutting machine embodying my improvements, shearing kerfs may be made in a mine entry or room wherein the roof is relatively low or no higher than necessary to provide clearance for the top of the machine, as shown in Fig. 17. Horizontal kerfs may also be cut in the face of a mine vein approximately in the plane of the roof where the latter is at a relatively low elevation, `as illustrated in Fig. 1a. It should be particularly noted, however, that as shown in Fig. 17, shearing kerfs and undercuts may be made in such low roof mine entries or rooms where there is just sufficient clearance for movement of the machine along the mine track.

Due to the pivotal relation of the turntable 33 with respect to the truck frame 28 about a vertical axis, and the pivotal connection of the cutter bar 21 to the neck turret 68 about the vertical axis of the cutter head turret 65, the cutter bar may be disposed at the mine bottom at either side of the mine track. That is to say, when the shaft 6|, shown in Fig. 5, is vertical, the horizontal spacing between the vertical turntable axis and the axis of the vertical shaft 6| enables the cutter bar to be disposed at the mine bottom at either side of the mine track rearwardly of the forward end thereof, and locked in such position. Then by operating the truck-propelling mechanism at a slow feeding speed the kerfcutter may be fed rectilinearly parallel to the mine track into the face of the mine vein extending across the space in advance of the mine track. This operation may be effected while the worm gearing shown in Fig. 5 locks the cutter bar in its adjusted position. At the end of the sumping feeding movement parallel to the mine track, the kerf-cutter may be fed arcuately either by mechanism for rotating the turntable or by the mechanism comprising the worm gearing |39, 94 for swinging the cutter bar on the axis of the shaft 6|.

After the completion of the arcuate feeding movement across the space in advance of the mine track, a rectilinear withdrawal feeding movement may be made by reversing the truckpropelling mechanism and controlling it to operate at the slow feeding speed.

By means of the rectilinear sumping and withdrawal kerf-cutting feeding movements connected by the arcuate transverse feeding movement, a parallel ribbed kerf may be cut with its bottom in continuation of the plane of the mine bottom. Such parallel ribbed kerfs may also be cut in horizontal planes at various elevations above the mine bottom by reason of the adjustments on the screw-posts 39, as illustrated in Figs. 3 and 4. Furthermore, when the neck turret 68' is turned over so that the cutter bar 21 occupies a top cutting position, parallel ribbed kerfs may be out in the lsame manner at various elevations. That is to say, the elevating mechanism comprising the screw-posts 39, enables kerfs to be cut at the mine bottom as shown in Fig. 1, and also at various elevations above the mine bottom within the range of operation of the screw-posts. In a similar manner, when the kerf-cutter is in the top cutting position shown in Fig. 1a horizontal kerfs may be cut in the plane illustrated in this view and also in various horizontal planes above the same within the limits of the screw-posts.

Parallel ribbed kerfs may also be cut in vertical planes parallel to the mine track, with the upper ribs of the kerfs at various elevations depending upon the height to which the outer end of the cutter bar 21 is adjusted.

The cutting of such shearing kerfs includes operation of the traction feed or slow feed propelling mechanism, and therefore the shearing kcrf may be either adjacent to one side of the mine track or adjacent to the other side thereof depending upon the adjusted position of the turnover head 68.

It should be particularly noted that the worm Wheel 12 is secured to the neck 58 and rotates therewith and that the take-off power-transmission mechanism from the shaft 48 to the worm wheel 12, is carried by the bracket 45 at the outer end of the radial auxiliary frame 45. This can be readily seen by referring to Figs. 13, 14, 15 and 16, Figs. 15 and 16 being taken on the lines |5|5 and |6|6 of Fig. 14 looking in the directions of the arrows. The weight of the mechanism carried by the neck 58 is thus reduced. It should also be noted that the brake |10 in Fig. 16 cooperates with the self-locking worm gearing to retain the neck 58 and mechanism carried thereby, in adjusted position relative to the cylindrical bearing 51', by counteracting creeping due to cutter bar vibrations during the various cutting operations fully explained above.

As shown in Figs. 2, 6 and 7, the housing |02 and bearing block |30 are rigidly connected to the neck 58 and turret 68 to move bodily therewith when the worm gear 12 is rotated on the cylindrical bearing 51. When the cutter bar is in a horizontal bottom cutting position the ho-using |02 shown in Fig. 7 occupies a vertical posi- The principal function of the brake mechanism |21, however, is to prevent vibrations of the cutter bar during swinging feeding movements, from rey,

tracting the shaft |06 during reverse impulses of the feeding pawl or ||2.

As shown in Fig. 7, the brake pulley |28 together with the brake mechanism |21 associated therewith, may be enclosed in annular recess |90 at the lower endk of the block |30. Retaining mechanism between the brake mechanism |21 and the block |30 is shown in Fig. 8 which isa sectional plan view taken on the line 8 9 of Fig. 7. A pin |9| rigidly secured to the block |30 to depend therefrom extends through a slot or opening in the strap |92 which is secured to the brake band intermediate its ends. The brake band itself may be lined with friction material |93 such as woven fabric. the free ends of the brake band are provided with holes through which extends the adjusting bolt |95. Between the lugs |94 and the bolt head |96 and the nut |91 are mounted compression springs |98, |98. By removing the screw plug |99 from an opening inthe casing |02 a socket wrench may be inserted and applied to the nut |91 to adjust the tension of the springs |98 which hold the brake-mechanism applied yieldingly to the brake pulley |28.

The power transmission mechanism for the turnover head mechanism and for the swinging of the cutter bar on the axis of the shaft 6| are very compactly arranged so'as not to require any space above a horizontal plane extending through the top of the support 45, and the brake mechanisms |21 and |10 are associated with such power transmission mechanisms while maintaining the overall height of the mining machine at a minimum, partcularly when the including Lugs |94 secured to kerf-cutter is in an undercutting position as shown in Figs. 1 and 5 and when in a shearing position as shown in Fig. 17. The dropped axis 51 together with this compact arrangement of parts, secures not only such reduced overall height but also a lower top cutting position of the kerf-cutter as illustrated in Fig. 1E.

As shown in the accompanying drawings various enclosing chambers are provided for the operation in oil of the trains of gears except the worm gearings 92, 12 and |39, 94 which are exposed. In Fig. 5, the enclosing chamber provided by the casing 68' enables the gearing 59, 60 to run in oil. In Fig. 13 the casing 83 affords an enclosing chamber for the gears 89, 90 to run in oil. At the right-hand end of Fig. 16, a lubricant enclosure for the gears 85, 90 is provided. It should be particularly noted, however, that the casing |02 of Fig. 7 is so mounted on the supplemental frame 68' (Figs. 5 and 6) as to provide an enclosure for the pawlA and ratchet feeding mechanism so that the latter may run in oil. For this purpose the lower end of the bearing block serves as a partition or closure for the bottom of the casing |02, the shafts IIS and |06 being journaled to extend outwardly from the casing |02 without permitting escape of the conned lubricant. This arrangement does not interfere with the very compact relation of the pawl and ratchet feeding mechanism at one side of the supplemental frame where it will occupy no greater head room than the top closure 03 of the casing 68' when the kerf-cutter is in the bottom-cutting position shown in Fig. 1. Furthermore, by shutting off the pawl and ratchet mechanism from the atmosphere in the mine chamber, dust cannot penetrate to the pawls and ratchets and tend to interfere with the feeding operations thereof.

The turret frame 68 provides a closed lubricant chamber for the gearing within the same. As shown in Fig. 6, a square-headed screwthreaded plug 200 normally closes a filling opening in the cover 63. In Fig. 13 a screw-threaded plug |0| normally closes a filling opening for the chamber in which the gear 13 is located. Lubricant may be drained from this chamber by removal of the screw-threaded plug 202. A lubricant fitting 203 may also be provided for the bearing of the gear 13, as shown in Fig. 13. It will thus be seen that lubricant will be retained in all of the lubricant enclosures irrespective of the position of the turnover head and cutter bar.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. In a mining mechanism, the combination with a frame, of a kerf cutter mounted for pivotal movement relative to said frame, means for swinging said kerf cutter relative to said frame and automatically locking it in any adjusted position comprising interlocking worm and worm gearing, means for driving said Worm comprising a shaft having friction brake means associated With one end thereof and pawl and ratchet means associated with the other end thereof, and means for supporting said shaft for free movement between said friction brake means and said pawl and ratchet means, said friction brake means operating to prevent reverse movement of said shaft when the ratchet of the pawl and ratchet mechanism makes a return stroke while permitting rotation thereof when said pawl makes a working stroke, and also operating to prevent creeping between said worm and worm gear under the influence of said kerf cutter when vibrating during operation.

2. In mining apparatus, the combination with a cutting tool, of supporting framework, means for adjustably supporting said cutting tool on said framework, means comprising pawl and ratchet feeding mechanism connected to selflocking worm gearing for adjusting the position of the cutting tool, and frictional braking means cooperating with a shaft and located between the pawl and ratchet feeding mechanism and the Worm gearing in position to exert a retarding effect on said worm gearing to prevent vibration of said cutting tool and thereby prevent relative creeping between the worm gear elements.

3. In a mining machine, the combination with a chain kerf cutter, of supporting framework, means for adjustably supporting said kerf cutter on said framework for swinging feeding movement, means comprising pawl and ratchet feeding mechanism connected to self-locking worm gearing for effecting swinging feeding movement of the chain kerf cutter, and an adjustable friction brake located on a shaft and between the pawl and ratchet feeding mechanism and said worm gearing for holding the chain kerf cutter against retrograde movement during operation of said pawl and ratchet feeding mechanism.

4. In a mining machine, the combination with a frame, of a head mounted on said frame, a kerf cutter mounted for swinging movement on said head, means for swinging said kerf cutter and locking it in any position of adjustment comprising a compact pawl and ratchet mechaanism, said mechanism including a shaft having a ratchet wheel at one end and a friction brake drum near the other end, a bearing block between the ratchet wheel and brake drum mounted as a unit therewith, a housing for said mechanism, means for attaching said bearing block in position in said housing, pawl means for driving said ratchet wheel, and friction brake means for applying friction to said brake drum.

5. A compact pawl and ratchet drive and brake mechanism for a mining machine comprising a housing, a shaft journaled intermediate its ends in a journal block, means removably attaching said block within said housing, a brake drum and a ratchet wheel mounted on said shaft on opposite sides of said block, friction means contacting said brake drum, and means including a pawl for actuating said ratchet wheel.

6. In a mining machine, the combination with a frame, of a kerf cutter, means for swinging said kerf cutter relative to said frame and locking it in adjusted position comprising a shaft, a drive gear on one end thereof and a ratchet Wheel on the other end, gear means driven by said gear for swinging said cutter bar, means including a pawl for operating said ratchet wheel, and brake means for restricting free rotation of said shaft including a drum rigidly attached thereto and located between the ratchet wheel and drive gear.

'7. A compact pawl ,and ratchet adjustable speed drive and brake mechanism for a mining machine comprising a housing, a shaft having a gear at one end and a ratchet wheel at the other end, friction brake means including a drum carried by said shaft intermediate said gear and ratchet Wheel, a journal block for said shaft supporting it intermediate said gear and ratchet Wheel, a pawl, a cup-shaped carrier for said pawl journaled in said housing, means for reciprocating said carrier and pawl, an adjustable cupshaped shield for variably determining the extent of rotation of said shaft for each reciprocation of said carrier and pawl, and means for adjusting said shield.

8. In a mining machine, the combination with cutting mechanism, of adjusting mechanism therefor comprising a driving shaft connected to a Worm meshing with a Worm Wheel, a journal bearing having an annular recess in one end, an annular brake member in said recess and surrounding said shaft and rigidly secured thereto to rotate therewith, and spring-pressed brake shoe mechanism within said recess and applied to the outside of said brake shoe member to hold the Worm and worm gear against relative movement during operation of said cutting mechanism.

9. In a mining machine, the combination with cutting mechanism, of adjusting mechanism therefor comprising a driving shaft connected to a worm meshing with a Worm Wheel, a brake member carried by said shaft to rotate therewith, brake shoe mechanism applied to said brake member outside thereof to hold the Worm and Worm wheel against relative movement during operation of said cutting mechanism and while said shaft is not being driven, means for adjusting said brake shoe mechanism, and an enclosure for the brake member and the brake shoe mechanism, said enclosure having an opening for the insertion of a tool for operating said adjusting means.

10. In a mining machine, the combination with cutting mechanism, of adjusting mechanism therefor comprising a driving shaft connected to a Worm meshing with a worm wheel, a support, a single pivot pin projecting from said support, and brake mechanism comprising a brake member connected to said shaft and a brake shoe pivoted to said pin.

1l. In a mining machine, the combination With cutting mechanism, of adjusting mechanism therefor comprising a driving shaft connected to a worm meshing with a worm wheel, a brake member connected to said shaft to rotate therewith, a brake shoe associated with the outside peripheral portion of said brake member, adjustable spring-pressed mechanism for yieldingly applying said brake shoe to said brake member to hold the Worm and worm wheel against relative movement during operation of said cutting mechanism and While said shaft is not driving, a support having an enclosure for said springpressed mechanism with an opening in such enclosure opposite said spring-pressed mechanism for the insertion of a tool to adjust the latter, and a removable device for closing said opening.

LEWIS E. MITCHELL. 

